Schultz Medical FAQs
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Electrocautery refers to direct current (electrons flowing in one direction) whereas electrosurgery uses alternating current. In electrosurgery, the patient is included in the circuit and current enters the patient’s body. During electrocautery, current does not enter the patient’s body.
With Monopolar Forceps , the active electrode is in the surgical site. The return electrode is elsewhere on the patient’s body.
The current passes through the patient as it completes the circuit from the active electrode to the return electrode.
With Bipolar Forceps , both the active electrode and return electrode functions are performed at the site of surgery.
The two tines of the forceps perform the active and return electrode functions. Only the tissue grasped is included in the electrical circuit.
Because the return function is performed by one tine of the forceps, no patient return electrode is needed.
Electrosurgical generators are capable of producing a variety of current waveforms. Depending on the clinical results desired, different waveforms can be used to produce differing tissue effects. An understanding of the ways in which the electrosurgical generator can modify current is necessary to better understand the options available to the surgeon.
Any current can be classified as either direct current or alternating (varying) current. Direct current is constant, never changing in direction (polarity) or magnitude. Direct current is the type produced by batteries. It is not used in electrosurgery because of its tendency to produce depolarization of neural and muscular tissue.
Alternating current is so named because its direction (polarity) changes (alternates). This type of current is similar to that which comes from electrical wall outlets. The rapidity with which the direction of current flow changes per unit of time is referred to as frequency, and is measured in Hertz (Hz). One complete cycle per second is one Hz. If a current alters polarity one million times per second, it is a one megahertz (MHz) current. Electrosurgical generators typically operate at frequencies between 400,000 Hz and 2.5 MHz, although some generators produce currents with frequencies as high as 3.5 MHz. Because these frequencies fall in the range of radio waves, electrosurgical generators are sometimes called radio frequency generators, and do, in fact, produce radio waves as a byproduct. Either excessively high or low frequencies can cause undesirable effects. Depolarization of susceptible tissues ceases at frequencies above 10,000 Hz. Excessively high frequencies tend to encourage current leakage.
Waveforms can be altered by the multiplication of two or more signals, a process called modulation. Damped and blended currents are examples of this process. There are three basic types of current waveforms used in electrosurgery: cutting current, coagulation current, and blended current.